uk citizen being sponsored by canadian citizen

hi there im from the uk and plan to apply from inside canada to be with my wife i would be so grateful if anyone can help me with a few issues that i have regarding my wife sponsoring me to be with her in canada.

my wife is working but she is paying back a student loan to the goverment will this affect our application in anyway.

i have 2 children from a previous relationship they will not be coming with me they will be staying in the uk with my ex partner my ex will not let me take the kids for there medicals can i get refused on this basis

and also do i need to get a Temporary Resident visa to enter canada or do i just explain at the immigration desk at the airport that im applying for a permenant visa from within canada

im looking forward to any answers

thank you